A chemical reaction system comprises: a supply source to generate a first carbon compound including at least one of carbon monoxide and carbon dioxide; an electrochemical reaction device to generate a second carbon compound including carbon monoxide by a reduction reaction of carbon dioxide; a reactor to generate a product including a third carbon compound by a chemical reaction of a reactant including hydrogen and at least one of the first and second carbon compounds; and a flow path through which the second carbon compound is supplied from the electrochemical reaction device to at least one of the supply source and the reactor.